Rheidae

genus of birds, ratites

species of bird

species of bird

Opisthodactylus is an extinct genus of rheiform bird from the Early to Middle Miocene Santa Cruz and Chichinales Formations and the Late Miocene (Montehermosan) Andalhuala Formation of Argentina. Three species are described: the type species, O. patagonicus, O. kirchneri and O. horacioperezi. The species O. kirchneri was described in 2017 by Noriega et al. Fossils of O. horacioperezi were found together with fossils of Patagorhacos terrificus.